Application that crashed: kmail
Version of the application: 1.12.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-17-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
1) Loading from hibernate with working KMail;
2) KMail try get messages from the server (IMAP) by timer;
2) KMail show message box that it can not connect to the server;
3) I press "OK"

This also occured if link is down and KMail try get message by timer 

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
The current source language is "auto; currently c".
[KCrash Handler]
#5  KIO::Slave::deref (this=0x24c03b0) at ../../kio/kio/slave.cpp:242
#6  0x00007f8d1b711159 in KIO::Slave::gotInput (this=0x24c03b0) at ../../kio/kio/slave.cpp:335
#7  0x00007f8d1b71326c in KIO::Slave::qt_metacall (this=0x24c03b0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffdb0c5ca0) at ./slave.moc:76
#8  0x00007f8d218b7ddc in QMetaObject::activate (sender=0x24da400, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x4ead0) at kernel/qobject.cpp:3113
#9  0x00007f8d1b62df57 in KIO::ConnectionPrivate::dequeue (this=0x24bf7d0) at ../../kio/kio/connection.cpp:82
#10 0x00007f8d1b62e07d in KIO::Connection::qt_metacall (this=0x24da400, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x2819670) at ./connection.moc:73
#11 0x00007f8d218b20f9 in QObject::event (this=0x24da400, e=0x280c4f0) at kernel/qobject.cpp:1111
#12 0x00007f8d21d35efc in QApplicationPrivate::notify_helper (this=0x169b930, receiver=0x24da400, e=0x280c4f0) at kernel/qapplication.cpp:4056
#13 0x00007f8d21d3d1ce in QApplication::notify (this=0x7fffdb0c6770, receiver=0x24da400, e=0x280c4f0) at kernel/qapplication.cpp:4021
#14 0x00007f8d23af8ab6 in KApplication::notify (this=0x7fffdb0c6770, receiver=0x24da400, event=0x280c4f0) at ../../kdeui/kernel/kapplication.cpp:302
#15 0x00007f8d218a2c2c in QCoreApplication::notifyInternal (this=0x7fffdb0c6770, receiver=0x24da400, event=0x280c4f0) at kernel/qcoreapplication.cpp:610
#16 0x00007f8d218a380a in QCoreApplication::sendEvent (receiver=0x0, event_type=<value optimized out>, data=0x160ed00) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#17 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=<value optimized out>, data=0x160ed00) at kernel/qcoreapplication.cpp:1247
#18 0x00007f8d218cb533 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#19 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:210
#20 0x00007f8d18b3bbce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#21 0x00007f8d18b3f598 in ?? () from /lib/libglib-2.0.so.0
#22 0x00007f8d18b3f6c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#23 0x00007f8d218cb1a6 in QEventDispatcherGlib::processEvents (this=0x160e930, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#24 0x00007f8d21dca4be in QGuiEventDispatcherGlib::processEvents (this=0x24c03b0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#25 0x00007f8d218a1532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#26 0x00007f8d218a1904 in QEventLoop::exec (this=0x7fffdb0c65a0, flags=) at kernel/qeventloop.cpp:201
#27 0x00007f8d218a3ab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#28 0x0000000000402fe9 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../kmail/main.cpp:146

Reported using DrKonqi